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djangodjango-signals

Can Django pre_save signal work for all derived classes

I have a model class "Action" that get's extended by several other classes. I am new to django and assumed that if I called pre_save.connect(actionFunc, sender=Action) that actionFunc would get called anytime the save method in the Action class was called (including by any derived class).

My observation is that this function only gets triggered when the instance is a direct match of the Class type defined in Sender. Is there anyway to get this to recieve signals for all derived instances of Action as well?

Solution

  • No, you have to call the pre_save.connect as many number of times.

    However, you can use python to get all the classes that extend the class of your interest, and loop over the pre_save connect statement.

    Say, if the extended classes of the Action are all in a given file, you can do the following:

    global_dict = globals().copy()
[el for el in global_dict.values() if getattr(el,'__base__',None)==Action]